Method of making indicia plaques



July 6, 1954 E. E. FRANZ METHOD OF' MAKING INDICIA PLAQUES Filed May 11.1950 anni s ....N .......tnvnn .....................nnn4un Oo/QQQQQNQNQNQW M0000 ollililll /NVENTR E. '.FRA/vz By limp MQ A TOR/vivPatented July 6, 1954 METHOD F MAKING INDICIA PLAQUES.

Erwin E. Franz, Cranford, N. J., assigner toWestern Electric Company,Incorporated, New York, N. Y., a corporation of New York -ApplicationMay 11, 1950, Serial No. 161,284

2 Claims. l

This invention relates to the marking of indicia and more particularlyto the engraving of indicia on resinous material by means of a heateddie.

Existing methods of providing an engraved marking usually involve llingthe engraved surface with a contrasting pigment, such as white lead inoil or a pigmented wax. In the so-called hot stamping process, themarking pigment is coated on the 'bottom of a paper sheet, and a die isused to simultaneously depress the surface and stamp the Idepressedsurface with the pigment. Although these methods are adequate, there hasbeen a need for a simple, economical method of providing an engravedsurface which would not require the addition of a pigment to fill theengraved portion, and it is an object of this invention to provide sucha method.

Applicant accomplishes his object according to the invention by makingparts to be marked of a resin such as those in the thermosettingpolyester group, the resins used being colored with a dark dye andfilled with a light colored shredded asbestos. When a heated diedesigned to produce the desired marking is pressed against the resinouspart, the resin and dye in contact with the die are disintegrated. Theasbestos which remains in the area of contact produces a light coloredimpression contrasting with the dark color of the main resin body, thusobviating the necessity of a lling pigment for setting off the marking.

IOther objects land features will be apparent from the followingdetailed description taken in conjunction with the attached drawing inwhich:

Fig. 1 is a perspective view of the resinous part after. the requiredmarking has been stamped thereon;

Fig. 2 is a bottom plan view of the marking die;

Fig. 3 is a front elevational view partly in section, showing themarking die in contact with the resinous part.

With reference to the drawing, the piece part I which is to be marked iscomposed primarily of a resinous material, such as any of thethermosetting polyester resins. The resinous material is then mixed witha ller having a white or gray color or other light color, such asshredded asbestos, the asbestos ller serving to add mechanical strengthto the combination. To this mixture is added a quantity of a dark dye,such as boneblack, to give a dark color to the resin. The compound isthen molded to the form required for the piece parts.

When it is desired to mark the parts I, they are brought into contactwith the marking die 2,

mounted or formed on a marking block 3. The die may be formed in anysuitable manner capable of creating an engraved impression in theresinous part I such as the marking shown i1 Fig. 1.

When the die, which has been heated to a temperature of approximatelydegrees C., is pressed against the part I, it causes the resinousmaterial and the boneblack in contact with the heated surf-ace of thedie to disperse or disintegrate. This leaves only the light coloredasbestos 4 in .the engraved portions, as the asbestos is not aiiected bythe heated die action. After the die has been pressed int-o the part forthe desired distance, it is withdrawn, leaving the engraved image orindicia in the light -colored asbestos which contrasts vividly with thedark color of the surrounding resinous compound with its boneblack dye.In the deeper impressions, i-t may sometimes be desirable to blow awaythe disintegrated resin and dye powder to bring out the colo-r contrastmore clearly. f

Applicant is unable to account for the disintegrating action whichtak-es place in the polyester resin and the boneblack, leaving only theasbestos image where the heated die has been applied. However, theinvention lies in the discovery that the coaction of a heated die and aresinous compound composed of. elements as described will result in asharply contrasting engraved marking, and is independent of the theoryunderlying the apparent disintegration of the resin and dye coloring.Applicant has discovered that the invention Works well withthermosetting resins of the polyester type, for example, but will notwork with phenolic resins, such as Bakelite. It is essential thereforethat the resinous material and dye used have a chemical structure whichwill disintegrate when brought into vcontact with a heated die.

As a result of various experiments carried out in connection with thisinvention, it has been determined that best results are obtained if thedie is heated to a temperature of between 120 to degrees C. If too low adie temperature is used, the resinous material will take longer to heatto the point of disintegration, and there will rbe a tendency for theoperator to press the die too hard against the part to speed up themarking which` will result in chipping of the resinous compound. A lowtemperature may also resul-t in an incomplete engraving. If thetemperature is too high, the impression loses its sions are made if theimpression edges of the dies are made with a fiat block type shaperather than with a V-shape. Use of the block type die avoids bulging andraising of the sides of the impression, as sometimes occurs with aV-shaped die surface when the initial heat is insuiiicient todisintegrate the resin. It also: requires less penetration of the part-to be marked, and provides a better color contrast because of its widerimpression.

By means of the invention, it is possible to' place engraved typeindicia onto. resinous. parts in a fast, economical manner, Withoutrequiring the addition of a pigmentA ller. The method is well adapted tomass production techniques, which accentuates the possible saving in=cost. In addition to serving as an element-in the process; the use ofshredded asbestos mixed with the resinous material also reduces theoverall cost since it is usually cheaper than the polyester resin.

It iste be understood that the above'described arrangements are simplyillustrative of the application of the principles-of the invention.Numerous other arrangements may be readily devised by those skilled inthe art which will embody the principles of the invention and fallvvitlf-iinA the spirit and scope thereof.

What is claimed is:

1,.. The method of making indicia in a thermosetting resin body of thepolyester class comprising homogeneously mixing the resin of a givencolor vvith an asbestos filler contrasting in color tothe resin, moldingthe mixture into a form of a giveny thickness and applying to the formanl object, having a contour of the indicia to be made, under a givenpressure and heated to a given temperature jointly sufficient todisintegrate the resin for a given depth in the form in the area engagedby the object leaving the indicia With clearly visible surfaces of theasbestos ller.

2. The method' of making indicia in a thermosetting resin bodyl of thepolyester class comprising homogeneously mixing the resin with a dye andan asbestos ller contrasting in color to the dye and. resin, molding themixture into a form of a given thickness and applying to the form anobject, having. a contour of the indicia to be made,` under ay givenpressure and heated to a giveny temperature jointly sufficient todisintegrate the resinior. a given depth in the form and dye in the areaengaged by the object leaving the indicia, with clearly visible surfacesof the exposed asbestos ller.

References Cited inthe le of this patent I`il\T[Ii`]iIDu STATES PATENTS

